Vehicle communication system, authentication control device, and vehicle communication method

Abstract

A communication unit (6) provided in a vehicle control device (5) periodically transmits a first command signal for requesting a response from a portable device (4) while a vehicle (2) is parked or stopped (S10). The portable device (4) transmits a first response signal upon receiving the first command signal. When the communication unit (6) receives the first response signal (S20: Yes), an authentication unit (7) executes a first user authentication (S30). When the first user authentication is established, the communication unit (6) periodically transmits a second command signal requesting a response from the portable device (4) and a position detection signal enabling detection of the distance from the vehicle (2) when the portable device (4) is in a predetermined area (20) (S70). When it is determined that the portable device (4) is in the predetermined area (20), the portable device (4) transmits a second response signal (S80). When the communication unit (6) receives the second response signal (S90: Yes), the authentication unit (7) executes a second user authentication, which has higher security than the first user authentication (S100).

Description

Vehicle communication system, authentication control device, and vehicle communication method CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application is based on Japanese Patent Application No. 2024-088264, filed on May 30, 2024, the contents of which are incorporated herein by reference.

[0002] The present disclosure relates to a vehicle communication system, an authentication control device, and a vehicle communication method.

[0003] Conventionally, a vehicle communication system is known that performs wireless communication with a portable device carried by a vehicle user while the vehicle is parked or stopped, and performs vehicle control such as welcome control and unlock control for the vehicle depending on the area where the portable device is located.

[0004] In general, a vehicle communication system periodically transmits a command signal from a communication unit of a vehicle to request a response from a portable device. The portable device then transmits a response signal upon receiving the command signal. When the communication unit of the vehicle receives the response signal, it performs user authentication to determine whether the portable device belongs to a legitimate user of the vehicle (see, for example, Patent Document 1).

[0005] Japanese Patent Application Laid-Open No. 2018-127798

[0006] However, in a vehicle communication system, when a user who has no intention of riding in the vehicle carries a portable device in an area far from the vehicle, if high-security authentication that consumes a lot of power is performed, there is a problem in that power consumption (i.e., dark current) increases while the vehicle is parked or stopped.

[0007] To solve this problem, the vehicular communication system described in Patent Document 1 implements control to prohibit the portable device from transmitting a response signal when communication between the vehicle's communication unit and the portable device continues for a predetermined period of time or longer. Also, the vehicular communication system described in Patent Document 1 implements control to cancel the prohibition on transmission of a response signal from the portable device when a user who enters the vicinity of the vehicle performs a predetermined operation on the portable device.

[0008] However, the vehicle communication system described in Patent Document 1 cannot detect the approach of a user when the transmission of a response signal from the portable device is prohibited. Therefore, there is a concern that if a user approaches the vehicle after the transmission of a response signal from the portable device is prohibited, vehicle functions such as vehicle unlocking control may become inoperable. Furthermore, in this vehicle communication system, the prohibition on the transmission of a response signal from the portable device is lifted by a predetermined operation by the user who enters the vicinity of the vehicle. Therefore, there is a risk that it may be difficult to provide vehicle functions such as welcome control, which are desirable when the user is in an area far from the vehicle.

[0009] An object of the present disclosure is to provide a vehicle communication system, an authentication control device, and a vehicle communication method that can reduce dark current while improving user convenience.

[0010] According to one aspect of the present disclosure, there is provided a vehicle communication system including a portable device carried by a vehicle user, and a vehicle control device that controls the vehicle by communicating wirelessly with the portable device, wherein the vehicle control device includes: a communication unit that communicates wirelessly with the portable device; and an authentication unit that performs user authentication to determine whether the portable device that transmitted the radio waves is the portable device carried by the vehicle user, based on a signal obtained from the communication unit; the communication unit periodically transmits a first command signal requesting a response from the portable device while the vehicle is parked or stopped; the portable device transmits a first response signal upon receiving the first command signal; and when the communication unit receives the first response signal, the authentication unit performs first user authentication to determine whether the portable device that transmitted the first response signal is the portable device carried by the vehicle user; and when the first user authentication is successful, the communication unit periodically transmits a second command signal requesting a response from the portable device when the portable device is in a predetermined area, and a position detection signal capable of detecting the distance from the vehicle, When the portable device receives the second command signal and the position detection signal and determines that the portable device is in a specified area based on the signal characteristics of the position detection signal, it transmits a second response signal, and when the communication unit receives the second response signal, the authentication unit performs second user authentication, which has higher security than the first user authentication.

[0011] According to this, the vehicular communication system can detect a portable device located in an area far from the vehicle through the first user authentication. Therefore, the vehicular communication system can execute vehicle functions (e.g., welcome control) that are preferable when the portable device is located in an area far from the vehicle, thereby improving user convenience. Furthermore, the first user authentication can be low-security authentication, thereby reducing dark current. Furthermore, the portable device transmits a second response signal when it determines that it is located in a predetermined area (e.g., an area near the vehicle) based on the second command signal and the position detection signal periodically transmitted after the first user authentication is established. In other words, the portable device does not transmit the second response signal when it is located in a distant area farther from the vehicle than the predetermined area. Therefore, the authentication unit of the vehicle control device does not perform the high-security (i.e., high-power-consumption) second user authentication when the portable device is located in the distant area, but performs the second user authentication upon receiving the second response signal when the portable device enters the predetermined area. Therefore, when the portable device is in the far area, the vehicular communication system continuously monitors the area where the portable device is located while preventing dark current consumption due to the second user authentication, and can immediately perform the second user authentication when the portable device enters the predetermined area. As a result, this vehicular communication system can improve user convenience and reduce dark current by appropriately providing vehicle functions corresponding to each of the far area and the near area.

[0012] According to another aspect of the present disclosure, an authentication control device controls the operation of a communication unit that communicates wirelessly with a portable device carried by a vehicle user, and performs user authentication to determine whether a portable device that transmitted radio waves is the portable device carried by the vehicle user, based on a signal obtained from the communication unit; while the vehicle is parked or stopped, the communication unit periodically transmits a first command signal requesting a response from the portable device; when the communication unit receives a first response signal transmitted from the portable device that received the first command signal, the device performs first user authentication to determine whether the portable device that transmitted the first response signal is the portable device carried by the vehicle user; when the first user authentication is successful, the communication unit periodically transmits a second command signal requesting a response from the portable device and a position detection signal that can detect the distance from the vehicle when the portable device is in a specified area; and when the portable device receives the second command signal and the position detection signal and determines that the portable device is in the specified area based on the signal characteristics of the position detection signal, the device performs second user authentication, which has higher security than the first user authentication.

[0013] As a result, the authentication control device according to another aspect of the present disclosure also achieves the same effects as the vehicle communication system according to one aspect of the present disclosure.

[0014] According to yet another aspect of the present disclosure, there is provided a vehicle communication method executed by a vehicle communication system including a portable device carried by a vehicle user and a vehicle control device that controls the vehicle by wirelessly communicating with the portable device, wherein the vehicle control device includes a communication unit that wirelessly communicates with the portable device and an authentication unit that performs user authentication to determine whether the portable device that transmitted the radio waves is the portable device carried by the vehicle user, based on a signal obtained from the communication unit; the communication unit periodically transmits a first command signal requesting a response from the portable device while the vehicle is parked or stopped; when the portable device receives the first command signal, the portable device transmits a first response signal; when the communication unit receives the first response signal, the authentication unit performs first user authentication to determine whether the portable device that transmitted the first response signal is the portable device carried by the vehicle user; and when the first user authentication is successful, the communication unit periodically transmits a second command signal requesting a response from the portable device when the portable device is in a predetermined area, and a position detection signal that can detect the distance from the vehicle; When the portable device receives the second command signal and the position detection signal and determines that the portable device is in a predetermined area based on the signal characteristics of the position detection signal, transmitting a second response signal from the portable device; and when the communication unit receives the second response signal, the authentication unit performs second user authentication, which has higher security than the first user authentication.

[0015] As a result, the vehicle communication method according to yet another aspect of the present disclosure also achieves the same effects as the vehicle communication system according to one aspect of the present disclosure.

[0016] FIG. 1 is an explanatory diagram for explaining a first area and a second area in a vehicle communication system according to a first embodiment. FIG. 2 is a block diagram of the vehicle communication system according to the first embodiment. FIG. 3 is a flowchart showing an example of a control process executed by the vehicle communication system according to the first embodiment. FIG. 4 is a time chart showing an example of a communication sequence of the vehicle communication system according to the first embodiment. FIG. 5 is a flowchart showing an example of a control process executed by the vehicle communication system according to a second embodiment. FIG. 6 is a flowchart showing an example of a control process executed by the vehicle communication system according to the second embodiment.

[0017] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. In the following embodiments, identical or equivalent parts will be denoted by the same reference numerals, and description thereof will be omitted.

[0018] First Embodiment A description will be given of a vehicle communication system 1 according to a first embodiment. As shown in Fig. 1, the vehicle communication system 1 performs wireless communication with a portable device 4 carried by a user 3 of a vehicle 2 while the vehicle 2 is parked or stopped, and performs vehicle control such as welcome control and unlock control for the vehicle depending on the area where the portable device 4 is located.

[0019] In the following description, an area that is a predetermined distance away from the vehicle 2 will be referred to as a first area 10, and a predetermined area that is closer to the vehicle 2 than the first area 10 will be referred to as a second area 20. The first area 10 may also be referred to as a distant area, and the second area 20 may also be referred to as a nearby area. In Figure 1, as indicated by the arrow M, a user 3 carrying a portable device 4 gradually approaches the vehicle 2 from an outer area 30 that is farther away than the first area 10.

[0020] First, we will explain the configuration of the vehicular communication system 1. As shown in Fig. 2, the vehicular communication system 1 includes a portable device 4 carried by a user 3 of a vehicle 2, and a vehicle control device 5 that wirelessly communicates with the portable device 4 and controls the vehicle 2.

[0021] The vehicle control device 5 includes a communication unit 6 and an authentication unit 7. The communication unit 6 is a component that performs wireless communication with the portable device 4 and includes a first communication unit 61 and a second communication unit 62. The first communication unit 61 performs wireless communication with the portable device 4 using a predetermined first communication method. The first communication method is, for example, LF / RF communication using long waves and high frequencies. Specifically, the first communication unit 61 includes an LF transmitter 63 and an RF receiver 64. LF stands for Low Frequency, i.e., long waves or low frequencies. RF stands for Radio Frequency, i.e., high frequencies. The first communication method employs a more power-saving communication method than the second communication method described below. The second communication unit 62 performs wireless communication with the portable device 4 using a second communication method that can measure the distance between the portable device 4 and the vehicle 2. The second communication method is, for example, UWB communication using an ultra-wideband frequency bandwidth. Specifically, the second communication unit 62 has a UWB transceiver unit 65. The UWB transceiver unit 65 is capable of measuring the distance between the portable device 4 and the vehicle 2 by the ToF method. ToF is an abbreviation for Time of Flight.

[0022] The authentication unit 7 is an electronic control device primarily composed of a microcomputer having a processor that performs control processing and arithmetic processing and a memory that stores programs, data, etc. Therefore, the authentication unit 7 may be referred to as an authentication control device or an authentication ECU. ECU stands for Electronic Control Unit. The processor is composed of a CPU or an MPU. The memory includes various non-transitory tangible storage media such as ROM, RAM, and non-volatile rewritable memory. The authentication unit 7 controls the operation of the communication unit 6 by executing a program stored in the memory. Based on a signal obtained from the communication unit 6, the authentication unit 7 performs user authentication to determine whether the portable device 4 that transmitted the radio waves is the portable device 4 carried by the user 3 of the vehicle 2. The authentication unit 7 performs first user authentication and second user authentication, which will be described later.

[0023] The portable device 4 is a portable key carried by the user 3 of the vehicle 2, and may be called a smart key, a key fob, a key card, an access key, or the like. The portable device 4 has a portable device communication unit 41 and a portable device control unit 42. The portable device communication unit 41 is a unit that performs wireless communication with the vehicle control device 5, and has a portable device first communication unit 43 and a portable device second communication unit 44. The portable device first communication unit 43 performs wireless communication with the first communication unit 61 using a first communication method. Specifically, the portable device first communication unit 43 has an LF receiving unit 45 and an RF transmitting unit 46. The portable device second communication unit 44 performs wireless communication with the second communication unit 62 of the vehicle control device 5 using a second communication method. Specifically, the portable device second communication unit 44 has a portable device UWB transceiver unit 47.

[0024] The portable device control unit 42 is mainly composed of a microcomputer (hereinafter referred to as "microcomputer") having a processor that performs control processing and arithmetic processing, and a memory that stores programs, data, etc. The portable device control unit 42 performs various control processing, which will be described later, by having the processor execute programs stored in the memory.

[0025] Next, the control process executed by the vehicle communication system 1 will be described with reference to the flowchart of Fig. 3. In the following description, steps will be simply represented as "S".

[0026] The vehicular communication system 1 executes the control process shown in FIG. 3 when the vehicle 2 is parked or stopped and a predetermined condition is met. As shown in the flowchart of FIG. 3 , in S10, the authentication unit 7 controls the first communication unit 61 to periodically transmit a first command signal from the LF transmission unit 63 of the first communication unit 61. In other words, the authentication unit 7 causes the LF transmission unit 63 to transmit the first command signal at a predetermined control time interval. The first command signal includes information required to activate the microcomputer of the portable device 4. The first command signal may also be referred to as a wake-up signal. The first command signal also includes information requesting a response from the portable device 4.

[0027] The first command signal is a radio wave signal that reaches the first area 10. Therefore, when the portable device 4 carried by the user 3 is within the first area 10, the LF receiving unit 45 of the portable device first communication unit 43 receives the first command signal.

[0028] The portable device 4's own vibration sensor or the like causes the microcomputer in the portable device control unit 42 to transition from a fully asleep state to a standby state in which it can receive a first command signal. Therefore, while the user 3 is carrying the portable device 4, the microcomputer in the portable device control unit 42 is in a standby state. When the LF receiver 45 of the portable device 4 receives the first command signal while the microcomputer is in the standby state, the portable device 4 fully activates its own microcomputer based on the information contained in the first command signal. Then, when the portable device 4 receives the first command signal while within the first area 10, the fully activated portable device control unit 42 controls the RF transmitter 46 to transmit a first response signal.

[0029] Next, in S20, the authentication unit 7 determines whether or not the RF receiver 64 of the first communication unit 61 has received a first response signal from the portable device 4. If the first response signal has not been received, the authentication unit 7 returns the process to S10. On the other hand, if the first response signal has been received, the authentication unit 7 proceeds to S30.

[0030] In S30, the authentication unit 7 performs first user authentication. The first user authentication is a process of determining whether the portable device 4 that transmitted the first response signal is the portable device 4 carried by the user 3 of the vehicle 2. In the first user authentication, the authentication unit 7 causes the first communication unit 61 to transmit a first challenge signal requesting identification information of the portable device 4 and a position detection signal capable of detecting the distance from the vehicle 2. The position detection signal is an unmodulated signal. When the portable device 4 receives the first challenge signal and the position detection signal at the portable device first communication unit 43, the portable device 4 transmits a first response signal including its own identification information and an area information signal indicating the area in which the portable device 4 is located. The area information signal is a signal indicating the result of detection of whether the portable device 4 is located in the first area 10 or the second area 20 based on the signal characteristics of the position detection signal. The signal strength (i.e., RSSI) of the position detection signal can be used as the signal characteristics of the position detection signal. RSSI is an abbreviation for received signal strength indicator or received signal strength indication. When the first communication unit 61 of the vehicle control device 5 receives the first response signal and the area information signal, the authentication unit 7 performs first user authentication by comparing the identification information sent from the portable device 4 with the identification information stored in the memory of the authentication unit 7. In the following description, the identification information stored in the memory of the authentication unit 7 is referred to as "vehicle-side identification information."

[0031] In S40, if the first user authentication is not successful, i.e., if the identification information sent from the portable device 4 does not match the identification information on the vehicle side, the authentication unit 7 returns the process to S10. On the other hand, if the first user authentication is successful in S40, i.e., if the identification information sent from the portable device 4 matches the identification information on the vehicle side, the authentication unit 7 proceeds to S50. Note that when the first communication unit 61 receives the first response signal and the first user authentication is successful, the authentication unit 7 determines that the portable device 4 is located in either the first area 10 or the second area 20. This enables the vehicle control device 5 to execute welcome control to support the occupant getting on the vehicle. The welcome control includes, for example, at least one of control to turn on the lights of the vehicle 2, control to set the vehicle driving motor to a ready state, and control to start the vehicle driving engine.

[0032] In S50, the authentication unit 7 starts measuring the time that has elapsed since the first user authentication was established. In S60, the authentication unit 7 determines whether the time that has elapsed since the first user authentication was established is within the validity period of the first user authentication. The validity period is pre-stored in the memory of the authentication unit 7.

[0033] In S60, if the time elapsed since the first user authentication was established exceeds the validity period of the first user authentication, the authentication unit 7 temporarily terminates the process. Then, the control process is executed again from S10. On the other hand, if the time elapsed since the first user authentication was established is within the validity period of the first user authentication, the authentication unit 7 proceeds to S70.

[0034] In S70, the authentication unit 7 controls the first communication unit 61 to periodically transmit a second command signal and a position detection signal from the LF transmission unit 63 of the first communication unit 61. In other words, the second command signal and the position detection signal are transmitted at predetermined control time intervals. The second command signal includes information requesting a response from the portable device 4 when the portable device 4 is in the second area 20, which is a predetermined area. The position detection signal is an unmodulated signal that can detect the distance from the vehicle 2.

[0035] In S80, when the portable device 4 receives the second command signal and the position detection signal via the portable device first communication unit 43, the portable device control unit 42 determines whether the portable device 4 is located in the second area 20. The portable device control unit 42 can determine whether the portable device 4 is located in the second area 20 based on the signal characteristics of the position detection signal. Specifically, the portable device control unit 42 can determine whether the portable device 4 is located in the second area 20 based on whether the signal strength of the position detection signal is equal to or greater than a predetermined threshold. The predetermined threshold is pre-stored in the memory of the portable device control unit 42. If the signal strength of the position detection signal is equal to or greater than the predetermined threshold, the portable device control unit 42 determines that the portable device 4 is located in the second area 20. In this case, the portable device 4 transmits a second response signal from the portable device first communication unit 43. On the other hand, if the signal strength of the position detection signal is less than the predetermined threshold, the portable device control unit 42 determines that the portable device 4 is not located in the second area 20. In this case, the portable device 4 does not transmit the second response signal. The first response signal and the second response signal may be the same signal or different signals.

[0036] Next, in S90, the authentication unit 7 of the vehicle control device 5 determines whether the first communication unit 61 has received a second response signal from the portable device 4. If the second response signal has not been received, the authentication unit 7 returns the process to S60. On the other hand, if the second response signal has been received, the authentication unit 7 proceeds to S100.

[0037] In S100, the authentication unit 7 performs second user authentication. The second user authentication is a process of determining whether the portable device 4 that transmitted the second response signal is the portable device 4 carried by the user 3 of the vehicle 2 using a method with higher security than the first user authentication. In the second user authentication, the authentication unit 7 causes the first communication unit 61 to transmit a second challenge signal requesting identification information of the portable device 4 and a position detection signal, and further causes the second communication unit 62 to measure the distance between the portable device 4 and the vehicle 2. Note that the position detection signal is an unmodulated signal. When the portable device first communication unit 43 receives the second challenge signal and the position detection signal, the portable device 4 transmits a second response signal including its own identification information and an area information signal indicating the area in which the portable device 4 is located. The area information signal is a signal indicating that the area in which the portable device 4 is located is the second area 20 based on the signal characteristics of the position detection signal. When the first communication unit 61 of the vehicle control device 5 receives the second response signal and the area information signal, the authentication unit 7 compares the identification information sent from the portable device 4 with the vehicle's identification information. The authentication unit 7 also confirms, based on the area information signal, that the portable device 4 is located in the second area 20. The authentication unit 7 further confirms that the measured distance between the portable device 4 and the vehicle 2, measured through wireless communication between the second communication unit 62 and the portable device second communication unit 44, is within the second area 20. Specifically, the UWB transceiver 65 of the second communication unit 62 performs ToF wireless communication with the portable device UWB transceiver 47 of the portable device second communication unit 44, and calculates the measured distance between the portable device 4 and the vehicle 2. If the identification information sent from the portable device 4 matches the identification information on the vehicle side, the area information signal confirms that the portable device 4 is in the second area 20, and the distance measured by the second communication unit 62 between the portable device 4 and the vehicle 2 is within the second area 20, then the second user authentication is established.

[0038] When the first communication unit 61 receives the second response signal and the second user authentication is established, the authentication unit 7 determines that the portable device 4 is in the second area 20. As a result, the vehicle control device 5 can execute control to automatically unlock the doors of the vehicle 2 (i.e., auto-unlock), or execute control to permit the doors to be unlocked by a user operation.

[0039] Next, the control process executed by the vehicle communication system 1 will be described with reference to the time chart of FIG.

[0040] When the vehicle 2 is parked or stopped and certain conditions are met, the authentication unit 7 provided in the vehicle control device 5 controls the first communication unit 61 to periodically transmit a first command signal Command1 from the LF transmission unit 63 of the first communication unit 61.

[0041] When the portable device 4 carried by the user 3 is within the first area 10, the LF receiving unit 45 of the portable device first communication unit 43 receives the first command signal Command 1. Then, upon receiving the first command signal Command 1, the portable device 4 transmits a first response signal ACK from the RF transmitting unit 46 under the control of the portable device control unit 42.

[0042] When the first communication unit 61 of the vehicle control device 5 receives the first response signal ACK, the authentication unit 7 performs first user authentication. In the first user authentication, the authentication unit 7 causes the first communication unit 61 to transmit a first challenge signal Challenge 1 requesting identification information of the portable device 4 and a position detection signal Burst. When the portable device 4 receives the first challenge signal Challenge 1 and the position detection signal Burst at the portable device-side first communication unit 43, the portable device 4 transmits a first response signal response OK and an area information signal Far Area. The first response signal response OK is a signal including its own identification information, and the area information signal Far Area is a signal indicating the area in which the portable device 4 is located. When the first communication unit 61 of the vehicle control device 5 receives the first response signal “response OK” and the area information signal “Far Area,” the authentication unit 7 compares the identification information sent from the portable device 4 with the identification information on the vehicle side. If the identification information sent from the portable device 4 matches the identification information on the vehicle side, the first user authentication is established.

[0043] When the first user authentication is successful, the authentication unit 7 periodically transmits a second command signal Command2 and a position detection signal Burst from the first communication unit 61. When the portable device 4 receives the second command signal Command2 and the position detection signal Burst via the portable device first communication unit 43, the portable device control unit 42 determines whether the portable device 4 is located in the second area 20. When the portable device 4 is located in an area outside the second area 20 (i.e., the first area 10 or the outer area 30), the portable device 4 determines that it is not located in the second area 20 and does not transmit a second response signal ACK. Note that in FIG. 4 , a dashed square indicates that the portable device 4 does not transmit a second response signal ACK. In contrast, when the user 3 carrying the portable device 4 moves from the first area 10 to the second area 20, the portable device 4 determines that it is located in the second area 20 and transmits a second response signal ACK. The first response signal ACK and the second response signal ACK may be the same signal or different signals.

[0044] When the first communication unit 61 of the vehicle control device 5 receives the second response signal ACK, the authentication unit 7 performs second user authentication. In the second user authentication, the authentication unit 7 causes the first communication unit 61 to transmit a second challenge signal Challenge 2 requesting identification information of the portable device 4 and a position detection signal Burst. The authentication unit 7 also causes UWB communication between the second communication unit 62 and the portable-device second communication unit 44 to measure the distance between the portable device 4 and the vehicle 2. When the portable device 4 receives the second challenge signal Challenge 2 and the position detection signal Burst at the portable-device first communication unit 43, the portable device 4 transmits a second response signal response OK and an area information signal Near Area. The second response signal response OK is a signal including its own identification information, and the area information signal Near Area is a signal indicating the area in which the portable device 4 is located. When the first communication unit 61 of the vehicle control device 5 receives the second response signal "response OK" and the area information signal "Near Area," the authentication unit 7 compares the identification information sent from the portable device 4 with the identification information on the vehicle side. The authentication unit 7 also confirms, based on the area information signal "Near Area," that the portable device 4 is located in the second area 20. The authentication unit 7 also confirms that the distance between the portable device 4 and the vehicle 2 measured through UWB communication between the second communication unit 62 and the portable device second communication unit 44 is within the second area 20. If the identification information sent from the portable device 4 matches the identification information on the vehicle side, the area information signal confirms that the portable device 4 is located in the second area 20, and the distance measured by the second communication unit 62 between the portable device 4 and the vehicle 2 is within the second area 20, the second user authentication is established.

[0045] The vehicle communication system 1 of the first embodiment described above provides the following advantages.

[0046] (1) In the first embodiment, while the vehicle 2 is parked or stopped, the communication unit 6 of the vehicle control device 5 periodically transmits a first command signal requesting a response from the portable device 4. When the portable device 4 receives the first command signal, it transmits a first response signal. When the communication unit 6 receives the first response signal, the authentication unit 7 performs first user authentication. When the first user authentication is successful, the communication unit 6 periodically transmits a second command signal and a signal for position detection. When the portable device 4 receives the second command signal and the signal for position detection and determines that the portable device 4 is in the second area 20, it transmits a second response signal. When the communication unit 6 receives the second response signal, the authentication unit 7 performs second user authentication, which has higher security than the first user authentication.

[0047] According to this configuration, the vehicular communication system 1 can detect the portable device 4 in the first area 10, which is far from the vehicle 2, through the first user authentication. Therefore, the vehicular communication system 1 can execute vehicle functions (e.g., welcome control) that are preferable to provide when the portable device 4 is in the first area 10, thereby improving convenience for the user 3. Furthermore, the first user authentication can be low-security authentication, thereby reducing dark current. Furthermore, the portable device 4 transmits a second response signal when it determines that it is in the second area 20 based on the second command signal and the position detection signal periodically transmitted after the first user authentication is established. In other words, the portable device 4 does not transmit the second response signal when it is located outside the second area 20. Therefore, the authentication unit 7 does not perform the second user authentication, which requires high security (i.e., high power consumption) when the portable device 4 is outside the second area 20, but performs the second user authentication upon receiving the second response signal when the portable device 4 enters the second area 20. Therefore, when the portable device 4 is outside the second area 20, the vehicular communication system 1 continuously monitors the area where the portable device 4 is located while preventing consumption of dark current due to the second user authentication, and can immediately perform the second user authentication when the portable device 4 enters the second area 20. As a result, the vehicular communication system 1 appropriately provides vehicle functions corresponding to each of the first area 10 and the second area 20, thereby improving convenience for the user 3 and reducing dark current.

[0048] (2) In the first embodiment, when the communication unit 6 receives a first response signal and the first user authentication is established, the vehicle control device 5 determines that the portable device 4 is located in either the first area 10 or the second area 20. Furthermore, when the communication unit 6 receives a second response signal and the second user authentication is established, the vehicle control device 5 determines that the portable device 4 is located in the second area 20. This allows the vehicular communication system 1 to appropriately provide vehicle functions corresponding to the first area 10 and the second area 20, thereby improving convenience for the user 3. Furthermore, the vehicular communication system 1 can reduce dark current by not performing the highly secure second user authentication until the portable device 4 enters the second area 20.

[0049] (3) In the first embodiment, the first command signal includes information necessary to start the microcomputer of the portable device 4. When the portable device 4 receives the first command signal, it starts its own microcomputer and transmits the first response signal. In this manner, the portable device 4 uses its own vibration sensor or the like to transition the microcomputer from a fully asleep state to a standby state in which it can receive the first command signal. Then, when the portable device 4 receives the first command signal while the microcomputer is in the standby state, the microcomputer is fully started up and is able to transmit the first response signal.

[0050] (4) In the first embodiment, the position detection signal is an unmodulated signal. The condition for the portable device 4 to transmit the second response signal is that the portable device 4 is determined to be in the second area based on the signal characteristics of the position detection signal when the signal strength of the position detection signal is equal to or greater than a predetermined threshold. This makes it possible to use the signal strength of the position detection signal as the signal characteristic of the position detection signal for determining the area of ​​the portable device 4.

[0051] (5) In the first embodiment, in the first user authentication, the authentication unit 7 causes the first communication unit 61 to transmit a first challenge signal requesting identification information of the portable device 4 and a position detection signal. When the portable device 4 receives the first challenge signal and the position detection signal, the portable device 4 transmits a first response signal including its own identification information and an area information signal indicating the area in which the portable device 4 is located. Then, when the first communication unit 61 receives the first response signal and the area information signal, the authentication unit 7 performs first user authentication by comparing the identification information transmitted from the portable device 4 with the identification information on the vehicle side. This allows the vehicle control device 5 to perform first user authentication with low power consumption using the first communication unit 61, which employs a communication method that is more power-efficient than the second communication method. Furthermore, the portable device 4 determines the area in which it is located and transmits the determination result to the vehicle control device 5 using the area information signal. Therefore, the vehicle control device 5 can detect the area in which the portable device 4 is located while performing first user authentication with low power consumption.

[0052] (6) In the first embodiment, when the first user authentication is successful, the vehicle control device 5 executes welcome control to support the occupant getting in. As a result, the vehicular communication system 1 can improve convenience for the user 3 by appropriately providing the welcome control as a vehicle function that is provided when the portable device 4 is located in the first area 10.

[0053] (7) In the first embodiment, the welcome control includes at least one of control for turning on the lights of the vehicle 2, control for putting the vehicle driving motor into a ready state, and control for starting the vehicle driving engine. This provides a specific example of the welcome control.

[0054] (8) In the first embodiment, in the second user authentication, the authentication unit 7 causes the first communication unit 61 to transmit a second challenge signal requesting identification information of the portable device 4 and a position detection signal, and further causes the second communication unit 62 to measure the distance between the portable device 4 and the vehicle 2. When the portable device 4 receives the second challenge signal and the position detection signal, the portable device 4 transmits a second response signal including its own identification information and an area information signal indicating the area in which the portable device 4 is located. When the first communication unit 61 receives the second response signal and the area information signal, the authentication unit 7 compares the identification information sent from the portable device 4 with the identification information on the vehicle side and confirms, based on the area information signal, that the portable device 4 is located within the second area 20. Furthermore, the authentication unit 7 performs the second user authentication based on the fact that the distance measured between the portable device 4 and the vehicle 2 by the second communication unit 62 is located within the second area 20. The first communication unit 61 transmits a first command signal, receives a first response signal, transmits a first challenge signal, and receives a first response signal using a first communication method that is more power-efficient than the second communication method. The first communication unit 61 also transmits a second command signal and a position detection signal, receives a second response signal, transmits a second challenge signal and a position detection signal, and receives a second response signal and an area information signal using the first communication method. This allows the vehicular communication system 1 to confirm that the portable device 4 is within the second area 20 based on the area information signal obtained by the first communication unit 61. Furthermore, the vehicular communication system 1 performs second user authentication based on the fact that the distance measured by the second communication unit 62 between the portable device 4 and the vehicle 2 is within the second area 20. This makes it possible to avoid, for example, relay attacks and perform highly secure second user authentication. In addition, the vehicle communication system 1 can reduce dark current by not performing the highly secure second user authentication until the portable device 4 enters the second area 20, and instead performing communication using the power-saving first communication method.

[0055] (9) In the first embodiment, when the second user authentication is successful, the vehicle control device 5 executes control to automatically unlock the doors of the vehicle 2 (i.e., auto-unlock) or executes control to permit the doors to be unlocked by a user operation. In this manner, the vehicular communication system 1 can improve convenience for the user 3 by appropriately providing the automatic unlocking control or the unlocking permission control as a vehicle function provided when the portable device 4 is located in the second area 20.

[0056] (10) In the first embodiment, the first communication method is LF / RF communication, and the second communication method is UWB communication. According to this, the first communication method is exemplified by LF / RF communication as a communication method capable of performing user authentication and the like with low power consumption. Furthermore, the second communication method is exemplified by UWB communication as a highly secure communication method. Since the ToF method is used for ranging using UWB communication, it is possible to avoid, for example, relay attacks and perform highly secure second user authentication.

[0057] Second Embodiment A second embodiment will be described. In the second embodiment, a part of the control processing executed by the vehicle communication system 1 is changed from that in the first embodiment, and the rest is the same as in the first embodiment. Therefore, only the parts that are different from the first embodiment will be described.

[0058] The control process executed by the vehicle communication system 1 of the second embodiment will be described with reference to the flowcharts of FIGS. 5A and 5B.

[0059] In S1, the vehicle control device 5 checks the state of the vehicle 2. Specifically, the vehicle control device 5 checks whether the vehicle 2 is parked or stopped. Next, in S2, the vehicle control device 5 determines whether all doors of the vehicle 2 are locked. If any door of the vehicle 2 is unlocked, the vehicle control device 5 returns the process to S1. On the other hand, if all doors of the vehicle 2 are locked, the vehicle control device 5 advances the process to S10.

[0060] In S10, the first communication unit 61 included in the vehicle control device 5 starts periodically transmitting a first command signal. Note that the processing from S10 to S100 is substantially the same as the processing described in the first embodiment, and therefore a description thereof will be omitted.

[0061] In S110 following S100, the vehicle control device 5 determines whether or not second user authentication has been established. If second user authentication has not been established, the process is temporarily terminated. Then, the control process is executed again from S1. On the other hand, if second user authentication has been established, the process proceeds to S120. In S120, the vehicle control device 5 determines whether or not the auto-unlock function is enabled. If the auto-unlock function is not enabled, the process is temporarily terminated. Then, the control process is executed again from S1. On the other hand, if the auto-unlock function is enabled, the process proceeds to S130. In S130, the vehicle control device 5 executes control to automatically unlock the doors of the vehicle 2 (i.e., auto-unlock).

[0062] The vehicle communication system 1 of the second embodiment described above can achieve the same effects as the first embodiment.

[0063] In the second embodiment, the first communication unit 61 included in the vehicle control device 5 starts periodic transmission of the first command signal when the vehicle 2 is parked or stopped and all doors of the vehicle 2 are locked. This exemplified a start condition for the control process by the vehicular communication system 1 being that the vehicle 2 is parked or stopped and all doors of the vehicle 2 are locked.

[0064] Furthermore, in the second embodiment, when the second user authentication is successful, the vehicle control device 5 executes control to automatically unlock the doors of the vehicle 2. As a result, the vehicular communication system 1 can improve convenience for the user 3 by providing the automatic unlocking control as a vehicle function when the portable device 4 is located in the second area 20.

[0065] (Other Embodiments) (1) In each of the above embodiments, the authentication unit 7 causes the first communication unit 61 to transmit the first challenge signal and the position detection signal in the first user authentication. However, this is not limited to this. For example, the authentication unit 7 may cause the first communication unit 61 to transmit the first challenge signal but not the position detection signal. In this case, the portable device 4 that receives the first challenge signal transmits the first response signal but does not transmit the area information signal. Then, when the first communication unit 61 receives the first response signal, the authentication unit 7 performs the first user authentication by comparing the identification information transmitted from the portable device 4 with the identification information on the vehicle side.

[0066] (2) In each of the above embodiments, the authentication unit 7 causes the first communication unit 61 to transmit a second challenge signal and a position detection signal and then causes the second communication unit 62 to measure the distance between the portable device 4 and the vehicle 2 during the second user authentication. However, this is not limited to this. For example, the authentication unit 7 may cause the first communication unit 61 to transmit the second challenge signal, not the position detection signal, and then cause the second communication unit 62 to measure the distance between the portable device 4 and the vehicle 2 during the second user authentication. In this case, the portable device 4 that receives the second challenge signal transmits a second response signal but does not transmit an area information signal. Then, when the first communication unit 61 receives the second response signal, the authentication unit 7 compares the identification information transmitted from the portable device 4 with the identification information on the vehicle side. The authentication unit 7 then performs the second user authentication by confirming that the distance measured by the second communication unit 62 between the portable device 4 and the vehicle 2 is within the second area 20.

[0067] (3) In the above embodiments, the second communication unit 62 employs UWB communication as the second communication method. However, the second communication method is not limited to UWB communication. For example, various communication methods capable of measuring the distance between the portable device 4 and the vehicle 2, such as BLE communication, may be employed. BLE is an abbreviation for Bluetooth (registered trademark) Low Energy.

[0068] The present disclosure is not limited to the above-described embodiments and can be modified as appropriate. Furthermore, the above-described embodiments and portions thereof are not unrelated to each other and can be combined as appropriate unless the combination is clearly impossible. It goes without saying that, in each of the above embodiments, the elements constituting the embodiments are not necessarily essential unless specifically stated as essential or clearly considered essential in principle. Furthermore, in each of the above embodiments, when numerical values ​​such as the number, values, amounts, and ranges of components of the embodiments are mentioned, they are not limited to the specific numbers unless specifically stated as essential or clearly limited to a specific number in principle. Furthermore, in each of the above embodiments, when the shape, positional relationship, etc. of components, etc. are mentioned, they are not limited to the shape, positional relationship, etc., unless specifically stated or limited to a specific shape, positional relationship, etc. in principle.

[0069] The control unit and the method described herein may be implemented by a special-purpose computer configured by configuring a processor and memory programmed to perform one or more functions embodied in a computer program. Alternatively, the control unit and the method described herein may be implemented by a special-purpose computer configured by configuring a processor with one or more dedicated hardware logic circuits. Alternatively, the control unit and the method described herein may be implemented by one or more special-purpose computers configured by combining a processor and memory programmed to perform one or more functions with a processor configured with one or more hardware logic circuits. Furthermore, the computer program may be stored as instructions executed by a computer on a computer-readable non-transitory tangible storage medium. The memory is a non-transitory tangible storage medium.

[0070] (Aspects of the Present Disclosure) The above-described present disclosure can be understood from the following aspects, for example. [First Aspect] A vehicle communication system including a portable device (4) carried by a user (3) of a vehicle (2) and a vehicle control device (5) that controls the vehicle through wireless communication with the portable device, wherein the vehicle control device includes: a communication unit (6) that wirelessly communicates with the portable device; and an authentication unit (7) that performs user authentication to determine whether the portable device that transmitted the radio waves is the portable device carried by the user of the vehicle, based on a signal obtained from the communication unit, wherein the communication unit periodically transmits a first command signal requesting a response from the portable device while the vehicle is parked or stopped (S10), the portable device transmits a first response signal when it receives the first command signal, and when the communication unit receives the first response signal (S20: Yes), the authentication unit performs first user authentication to determine whether the portable device that transmitted the first response signal is the portable device carried by the user of the vehicle (S30), When the first user authentication is successful, the communication unit periodically transmits a second command signal requesting a response from the portable device when the portable device is in a specified area, and a position detection signal capable of detecting the distance from the vehicle (S70); when the portable device receives the second command signal and the position detection signal and determines that the portable device is in the specified area based on the signal characteristics of the position detection signal, it transmits a second response signal (S80); when the communication unit receives the second response signal (S90: Yes), the authentication unit performs second user authentication, which has higher security than the first user authentication (S100), a vehicle communication system. [Second Aspect] When an area that is a predetermined distance away from the vehicle is called a first area (10) and the predetermined area that is closer to the vehicle than the first area is called a second area (20), the vehicle control device determines that the portable device is located in either the first area or the second area when the communication unit receives the first response signal and the first user authentication is established, and determines that the portable device is located in the second area when the communication unit receives the second response signal and the second user authentication is established, in the vehicle communication system described in the first aspect.[Third Aspect] The vehicle communication system according to the first or second aspect, wherein the first command signal includes information required to activate a microcomputer of the portable device, and the portable device activates its own microcomputer upon receiving the first command signal and transmits the first response signal. [Fourth Aspect] The vehicle communication system according to any one of the first to third aspects, wherein the position detection signal is an unmodulated signal, and a condition for the portable device to transmit the second response signal is that the portable device has determined, based on the signal characteristics of the position detection signal, that it is located in the predetermined area when the signal strength of the position detection signal is equal to or greater than a predetermined threshold. [Fifth Aspect] In the first user authentication, the authentication unit causes the communication unit to transmit a first challenge signal requesting identification information of the portable device, and when the portable device receives the first challenge signal, the portable device transmits a first response signal including its own identification information. When the communication unit receives the first response signal, the authentication unit performs the first user authentication by comparing the identification information sent from the portable device with identification information stored in a memory of the authentication unit. [Sixth Aspect] The vehicle communication system according to any one of the first to fourth aspects, wherein, in the first user authentication, the authentication unit causes the communication unit to transmit a first challenge signal requesting identification information of the portable device and the signal for location detection, the portable device, upon receiving the first challenge signal and the signal for location detection, transmits a first response signal including its own identification information and an area information signal indicating an area in which the portable device is located determined based on signal characteristics of the signal for location detection, and when the communication unit receives the first response signal and the area information signal, the authentication unit performs the first user authentication by comparing the identification information transmitted from the portable device with identification information stored in a memory of the authentication unit. [Seventh Aspect] The vehicle communication system according to any one of the first to sixth aspects, wherein, when the first user authentication is successful, the vehicle control device executes welcome control to support a passenger getting into the vehicle.[Eighth Aspect] The vehicle communication system according to the seventh aspect, wherein the welcome control includes at least one of control for turning on lights of the vehicle, control for putting a vehicle driving motor into a ready state, and control for starting an engine for driving the vehicle. [Ninth Aspect] The communication unit has a first communication unit (61) that performs wireless communication with the portable device using a predetermined first communication method, and a second communication unit (62) that performs wireless communication with the portable device using a second communication method that can measure the distance between the portable device and the vehicle, and the authentication unit, in the second user authentication, causes the first communication unit to transmit a second challenge signal requesting identification information of the portable device, and further causes the second communication unit to measure the distance between the portable device and the vehicle, and when the portable device receives the second challenge signal, the portable device transmits a second response signal including its own identification information, and when the first communication unit receives the second response signal, the authentication unit compares the identification information sent from the portable device with the identification information stored in a memory of the authentication unit, and further performs the second user authentication based on the measured distance between the portable device and the vehicle measured by the second communication unit being within the predetermined area, The vehicle communication system according to the fifth or sixth aspect, wherein the first communication unit transmits the first command signal, receives the first response signal, transmits the first challenge signal, receives the first response signal, transmits the second command signal and the position detection signal, receives the second response signal, transmits the second challenge signal, and receives the second response signal using the first communication method, which is more power-efficient than the second communication method.[Tenth Aspect] The communication unit has a first communication unit (61) that performs wireless communication with the portable device using a predetermined first communication method, and a second communication unit (62) that performs wireless communication with the portable device using a second communication method that can measure the distance between the portable device and the vehicle, and the authentication unit, in the second user authentication, causes the first communication unit to transmit a second challenge signal requesting identification information of the portable device and the position detection signal, and further causes the second communication unit to measure the distance between the portable device and the vehicle, and when the portable device receives the second challenge signal and the position detection signal, the portable device transmits a second response signal including its own identification information and an area information signal that indicates an area in which the portable device is located, determined based on signal characteristics of the position detection signal, When the first communication unit receives the second response signal and the area information signal, the authentication unit compares the identification information sent from the portable device with the identification information stored in the memory of the authentication unit, confirms that the portable device is within the specified area based on the area information signal, and further performs the second user authentication based on the fact that the distance measured by the second communication unit between the portable device and the vehicle is within the specified area; and the first communication unit transmits the first command signal, receives the first response signal, transmits the first challenge signal, receives the first response signal, transmits the second command signal and the position detection signal, receives the second response signal, transmits the second challenge signal and the position detection signal, and receives the second response signal and the area information signal using the first communication method, which is more power-efficient than the second communication method. [Eleventh Aspect] The vehicle communication system according to any one of the first to tenth aspects, wherein the vehicle control device executes control to automatically unlock the doors of the vehicle or executes control to allow the doors to be unlocked by a user operation when the second user authentication is successful. [Twelfth Aspect] The vehicle communication system according to any one of the first to eleventh aspects, wherein the communication unit starts periodically transmitting the first command signal when the vehicle is parked or stopped and all of the doors of the vehicle are locked.[Thirteenth Aspect] The vehicle communication system according to the ninth or tenth aspect, wherein the first communication method is LF / RF communication using long waves and high frequencies, and the second communication method is UWB communication using an ultra-wideband frequency bandwidth. [Fourteenth Aspect] An authentication control device (7) that controls the operation of a communication unit (6) that wirelessly communicates with a portable device (4) carried by a user (3) of a vehicle (2) and performs user authentication to determine whether the portable device that transmitted radio waves is the portable device carried by the user of the vehicle, based on a signal obtained from the communication unit, includes: while the vehicle is parked or stopped, causing the communication unit to periodically transmit a first command signal requesting a response from the portable device (S10); when the communication unit receives a first response signal transmitted from the portable device that received the first command signal (S20: Yes), performing first user authentication to determine whether the portable device that transmitted the first response signal is the portable device carried by the user of the vehicle (S30); and when the first user authentication is successful, causing the communication unit to periodically transmit a second command signal requesting a response from the portable device and a position detection signal capable of detecting a distance from the vehicle when the portable device is in a predetermined area (S70); When the portable device receives the second command signal and the position detection signal and determines that the portable device is in the specified area based on the signal characteristics of the position detection signal, and when the communication unit receives a second response signal transmitted from the portable device (S90: Yes), an authentication control device performs a second user authentication with higher security than the first user authentication (S100).[Fifteenth Aspect] A vehicle communication method executed by a vehicle communication system (1) including a portable device (4) carried by a user (3) of a vehicle (2) and a vehicle control device (5) that controls the vehicle by wirelessly communicating with the portable device, wherein the vehicle control device includes a communication unit (6) that wirelessly communicates with the portable device, and an authentication unit (7) that performs user authentication to determine whether the portable device that transmitted the radio waves is the portable device carried by the user of the vehicle, based on a signal obtained from the communication unit, the method comprising: periodically transmitting, by the communication unit, a first command signal that requests a response from the portable device while the vehicle is parked or stopped (S10); transmitting a first response signal from the portable device when the portable device receives the first command signal; and, when the communication unit receives the first response signal (S20: Yes), performing first user authentication by the authentication unit to determine whether the portable device that transmitted the first response signal is the portable device carried by the user of the vehicle (S30). When the first user authentication is successful, the communication unit periodically transmits a second command signal requesting a response from the portable device when the portable device is in a predetermined area, and a position detection signal capable of detecting a distance from the vehicle (S70); when the portable device receives the second command signal and the position detection signal and determines that the portable device is in the predetermined area based on signal characteristics of the position detection signal, the communication unit transmits a second response signal from the portable device (S80); and when the communication unit receives the second response signal (S90: Yes), the authentication unit performs second user authentication having higher security than the first user authentication (S100).

[0071] It should be noted that the above fourteenth and fifteenth aspects can be arbitrarily combined with the contents of the second to thirteenth aspects.

Claims

1. A vehicle communication system including a portable device (4) carried by a user (3) of a vehicle (2), and a vehicle control device (5) that controls the vehicle by communicating wirelessly with the portable device, wherein the vehicle control device includes a communication unit (6) that communicates wirelessly with the portable device, and an authentication unit (7) that performs user authentication to determine whether the portable device that transmitted the radio waves is the portable device carried by the user of the vehicle, based on a signal obtained from the communication unit, wherein the communication unit periodically transmits a first command signal requesting a response from the portable device while the vehicle is parked or stopped (S10), the portable device transmits a first response signal when it receives the first command signal, and when the communication unit receives the first response signal (S20: Yes), the authentication unit performs first user authentication to determine whether the portable device that transmitted the first response signal is the portable device carried by the user of the vehicle (S30), When the first user authentication is successful, the communication unit periodically transmits a second command signal requesting a response from the portable device when the portable device is in a specified area (20) and a position detection signal capable of detecting the distance from the vehicle (S70); when the portable device receives the second command signal and the position detection signal and determines that the portable device is in the specified area based on the signal characteristics of the position detection signal, it transmits a second response signal (S80); when the communication unit receives the second response signal (S90: Yes), the authentication unit performs second user authentication, which has higher security than the first user authentication (S100), a vehicle communication system.

2. The vehicle communication system of claim 1, wherein an area that is a predetermined distance away from the vehicle is called a first area (10) and the predetermined area that is closer to the vehicle than the first area is called a second area (20), the vehicle control device determines that the portable device is located in either the first area or the second area when the communication unit receives the first response signal and the first user authentication is established, and determines that the portable device is located in the second area when the communication unit receives the second response signal and the second user authentication is established.

3. A vehicle communication system as described in claim 1 or 2, wherein the first command signal includes information necessary to start up a microcomputer in the portable device, and when the portable device receives the first command signal, it starts up its own microcomputer and transmits the first response signal.

4. A vehicle communication system as described in claim 1 or 2, wherein the position detection signal is an unmodulated signal, and the condition for the portable device to transmit the second response signal is that the portable device determines that it is in the specified area based on the signal characteristics of the position detection signal when the signal strength of the position detection signal is equal to or greater than a specified threshold.

5. A vehicle communication system as described in claim 1 or 2, wherein, in the first user authentication, the authentication unit causes the communication unit to transmit a first challenge signal requesting identification information of the portable device, and when the portable device receives the first challenge signal, it transmits a first response signal including its own identification information, and when the communication unit receives the first response signal, the authentication unit performs the first user authentication by comparing the identification information sent from the portable device with the identification information stored in the memory of the authentication unit.

6. A vehicle communication system as described in claim 1 or 2, wherein, in the first user authentication, the authentication unit causes the communication unit to transmit a first challenge signal requesting identification information of the portable device and the position detection signal, and when the portable device receives the first challenge signal and the position detection signal, the portable device transmits a first response signal including its own identification information and an area information signal indicating the area in which the portable device is located, determined based on the signal characteristics of the position detection signal, and when the communication unit receives the first response signal and the area information signal, the authentication unit performs the first user authentication by comparing the identification information sent from the portable device with the identification information stored in the memory of the authentication unit.

7. The vehicle communication system according to claim 1 or 2, wherein the vehicle control device executes welcome control to support the occupant getting on the vehicle when the first user authentication is successful.

8. The vehicle communication system according to claim 7, wherein the welcome control includes at least one of control for turning on the vehicle's lights, control for putting the vehicle's driving motor into a ready state, and control for starting the vehicle's driving engine.

9. The communication unit has a first communication unit (61) that communicates wirelessly with the portable device using a predetermined first communication method, and a second communication unit (62) that communicates wirelessly with the portable device using a second communication method that can measure the distance between the portable device and the vehicle, and the authentication unit, in the second user authentication, causes the first communication unit to transmit a second challenge signal requesting identification information of the portable device, and further causes the second communication unit to measure the distance between the portable device and the vehicle, and when the portable device receives the second challenge signal, it transmits a second response signal including its own identification information, and when the first communication unit receives the second response signal, the authentication unit compares the identification information sent from the portable device with the identification information stored in the memory of the authentication unit, and further performs the second user authentication based on the distance measured by the second communication unit between the portable device and the vehicle being within the predetermined area, 6. The vehicle communication system according to claim 5, wherein the first communication unit transmits the first command signal, receives the first response signal, transmits the first challenge signal, receives the first response signal, transmits the second command signal and the position detection signal, receives the second response signal, transmits the second challenge signal, and receives the second response signal using the first communication method, which is more power-efficient than the second communication method.

10. The communication unit has a first communication unit (61) that performs wireless communication with the portable device using a predetermined first communication method, and a second communication unit (62) that performs wireless communication with the portable device using a second communication method that can measure the distance between the portable device and the vehicle, and the authentication unit, in the second user authentication, causes the first communication unit to transmit a second challenge signal requesting identification information of the portable device and the position detection signal, and further causes the second communication unit to measure the distance between the portable device and the vehicle, and when the portable device receives the second challenge signal and the position detection signal, it transmits a second response signal including its own identification information and an area information signal indicating the area in which the portable device is located, determined based on the signal characteristics of the position detection signal, 6. The vehicle communication system according to claim 5, wherein, when the first communication unit receives the second response signal and the area information signal, the authentication unit compares the identification information sent from the portable device with the identification information stored in the memory of the authentication unit, confirms that the portable device is within the specified area based on the area information signal, and further performs the second user authentication based on the fact that the distance measured by the second communication unit between the portable device and the vehicle is within the specified area; and the first communication unit transmits the first command signal, receives the first response signal, transmits the first challenge signal, receives the first response signal, transmits the second command signal and the position detection signal, receives the second response signal, transmits the second challenge signal and the position detection signal, and receives the second response signal and the area information signal using the first communication method, which is more power-efficient than the second communication method.

11. A vehicle communication system as described in claim 1 or 2, wherein the vehicle control device, when the second user authentication is successful, executes control to automatically unlock the vehicle doors or executes control to allow the doors to be unlocked by user operation.

12. The vehicle communication system according to claim 1 or 2, wherein the communication unit starts periodically transmitting the first command signal when the vehicle is parked or stopped and all doors of the vehicle are locked.

13. The vehicle communication system according to claim 9, wherein the first communication method is LF / RF communication using long waves and high frequencies, and the second communication method is UWB communication using an ultra-wideband frequency bandwidth.

14. An authentication control device (7) that controls the operation of a communication unit (6) that communicates wirelessly with a portable device (4) carried by a user (3) of a vehicle (2) and performs user authentication based on a signal obtained from the communication unit to determine whether the portable device that transmitted radio waves is the portable device carried by the user of the vehicle, comprises: while the vehicle is parked or stopped, the communication unit periodically transmits a first command signal requesting a response from the portable device (S10); when the communication unit receives a first response signal transmitted from the portable device that received the first command signal (S20: Yes), first user authentication is performed to determine whether the portable device that transmitted the first response signal is the portable device carried by the user of the vehicle (S30); and when the first user authentication is successful, the communication unit periodically transmits a second command signal requesting a response from the portable device and a position detection signal capable of detecting the distance from the vehicle when the portable device is in a predetermined area (20) (S70); When the portable device receives the second command signal and the position detection signal and determines that the portable device is in the specified area based on the signal characteristics of the position detection signal, and when the communication unit receives a second response signal transmitted from the portable device (S90: Yes), an authentication control device performs a second user authentication with higher security than the first user authentication (S100).

15. A vehicle communication method executed by a vehicle communication system (1) including a portable device (4) carried by a user (3) of a vehicle (2) and a vehicle control device (5) that controls the vehicle by communicating wirelessly with the portable device, wherein the vehicle control device includes a communication unit (6) that communicates wirelessly with the portable device, and an authentication unit (7) that performs user authentication to determine whether the portable device that transmitted the radio waves is the portable device carried by the user of the vehicle based on a signal obtained from the communication unit, the method comprising: periodically transmitting a first command signal by the communication unit while the vehicle is parked or stopped (S10) requesting a response from the portable device; transmitting a first response signal from the portable device when the portable device receives the first command signal; and, when the communication unit receives the first response signal (S20: Yes), performing first user authentication by the authentication unit to determine whether the portable device that transmitted the first response signal is the portable device carried by the user of the vehicle (S30). When the first user authentication is established, the communication unit periodically transmits a second command signal requesting a response from the portable device when the portable device is in a predetermined area (20), and a position detection signal capable of detecting a distance from the vehicle (S70); when the portable device receives the second command signal and the position detection signal and determines that the portable device is in the predetermined area based on the signal characteristics of the position detection signal, the communication unit transmits a second response signal from the portable device (S80); and when the communication unit receives the second response signal (S90: Yes), the authentication unit performs second user authentication having higher security than the first user authentication (S100).

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